This invention relates to lasers and more particularly to a conductively cooled lamp pumped rod-type laser.
There has been a continuing problem with conductively cooled solid state lasers in the removal of heat from the optically pumped laser rod. Heat should be transferred efficiently to the supporting rod heat sink by a low resistance thermal path in such a manner as to minimize or eliminate mechanical strain in the rod due to differences in the thermal expansion of the rod and heat sink. At the same time, a mechanically stable rod mount that will withstand vibration and other movements is required. This invention is directed to a structure which meets these requirements.
In addition to the above, there is a need in such lasers for efficient coupling of pump lamp radiation at the desired wavelength to the rod as well as removal of lamp radiation at undesired wavelengths to the adjacent parts of the laser housing. Prior art lasers of this type have utilized a dielectric elliptically shaped shell with a coating that reflects to the rod only the desired pump wavelengths, such technique being described in an article entitled "Dielectric Cavity Raises YAG Cavity Efficiency", by Y. H. Hahn et al published in Electro-Optical Systems Design, February 1975 (Milton S. Kiver Publications). Such lasers, however, have depended upon convection cooling of the shell; that is, the shell is simply exposed to the air or other similar medium. There is no known technique in the prior art for enclosing such a shell in a conductively cooled housing and to do so in such a manner as to preserve the efficient transfer of heat from the shell to the body.
Another aspect of the above type of conductively cooled lasers is the need for accessibility of parts for maintenance and repair without compromising the capability of the assembly to withstand vibration and shock forces. In one prior art pump assembly, a plurality of glass inserts were cemented to the inner surface of the elliptical bore of the housing. Replacement of these inserts required complete disassembly of the structure and reprocessing of the bore which is not only costly and time-consuming but also is difficult to accomplish in the field. This invention is directed to a solution to this problem.